(i) Field of the Invention
The present invention relates to novel pharmaceutical compounds and more particularly to controlled substances that are covalently bound to a chemical moiety and thus rendered pharmaceutically inactive until broken down by enzymatic and/or chemical means in a time-dependent manner following oral administration. Delayed release from the conjugate prevents spiking of drug levels and affords gradual release over an extended period of time. The enzymatic and/or chemical conditions necessary for the release of the controlled substance are either not present or of minimal activity when the novel pharmaceutical compound is introduced nasally, inhaled, or injected; thus, also preventing spiking when administered by these routes. Controlled substances with these novel properties are less likely to be abused due to the diminished “rush” effect of the modified controlled substance. Consequently, the therapeutic value of these pharmaceuticals is enhanced by decreasing euphoria while increasing the duration of the analgesic effect.
(ii) Description of the Related Art
A number of pharmacologically useful compounds are also commonly abused controlled substances. In particular, analgesics that are prescribed for the management of acute and chronic pain have become increasingly abused over the last decades. For example, the increase in prescription of oxycodone in the last few years led to widespread abuse of this drug. Amphetamines are another example of controlled substances with important pharmacological uses that are highly addictive and commonly abused.
There is considerable information readily available to individuals which teaches how to derive purified forms of controlled substances from prescription products. These techniques are both simple and well described on multiple websites. Most of these procedures utilize cold water, although, hot water, changes in pH and other solvents are described. Examples of these procedures are described below.
The description of these procedures was found on the web in February of 2003 at http://codeine.50g.com/info/extraction.html#ex.coldw and is paraphrased below. Cold water extraction is used to extract an opiate/opioid substance from combination tablets. This method subverts the fact that opiates are generally very soluble in cold water, while paracetamol, aspirin, and ibuprofen are only very slightly soluble. These techniques are sophisticated enough to recognize that pseudoephedrine and caffeine are water soluble and will remain in the solution and that dispersible tablets make it difficult to extract secondary substances. The description of the equipment required makes it clear that these procedures make abuse readily available. The equipment includes a minimum two glasses or cups, paper filters (unbleached coffee filters will do) and a measure glass. Portions of the procedures are provided below:                1. Crush the tablets and dissolve in cold (20° C.) water.        2. Cool the solution down to approximately 5° C. stirring occasionally.        3. Leave the solution in a cool place for about 20 minutes.        4. Wet the filter(s) with very cold water to prevent it from absorbing the solution and put it in the glass. Stick an elastic/rubber band around the container to keep the filter in place.        5. Pour the solution through the filter to filter out the secondary substance from codeine.        6. Discard used filters with secondary substance solids left.        
However, when these procedures were viewed as not providing sufficient yields improved method were designed for extracting codeine which simply require the addition of chloroform or like solvent such as methylene chloride. This technique utilizes methods which alter the pH aspects of the solution to improve extraction and even provides instruction on how to re-salt the product. Portions of the procedure are described below.                1. Place uncrushed T3's or other APAP/codeine product in a small glass or beaker and cover with enough distilled water so that the pills will break down into a thin paste.        2. Add dry sodium carbonate to reduce the codeine phosphate to codeine base. The pH of the mixture should be about 11 or greater.        3. Pour the mixture into the pyrex pan and rinse the beaker with a few ml of distilled water and add the rinse water to the mix in a pan.        4. Wrap the dried material in a coffee filter and grind the stuff        5. Pour the dry crushed mixture into a glass bottle with a screw-on top and pour in enough chloroform to completely cover.        6. Shake and filter.        
While there has been considerable effort to provide controlled substances which are resistance to abuse current products fail to achieve the stability required to prevent abuse. The present invention however, provides methods and compositions which retain their stability even when subjected to current abuse methods, and therefore provide a much needed but less addictive and/or less likely to be abused product.